Objective To study the rational daily administration times of Yinchenhao Decoction(YCHD)when it was used to treat experimental jaundice in rats based on pharmacodynamics/pharmacokinetics model.Methods Rats were modele...Objective To study the rational daily administration times of Yinchenhao Decoction(YCHD)when it was used to treat experimental jaundice in rats based on pharmacodynamics/pharmacokinetics model.Methods Rats were modeled by 4%1-naphthylisothiocyanate(75 mg/kg)for 48 h,then YCHD was drenched with doses of 0.324 g/kg (extract,calculated with the clinical dosage)once,0.162 g/kg twice,and 0.108 g/kg thrice a day,respectively.The total bile and the flow rate of bile were observed after the first administration;Blood samples collected from the orbital sinus at different intervals were used to investigate the levels of liver enzymes(ALT and AST)and bilirubins (TBIL and DBIL),and determine the concentration of 6,7-dimethoxycoumarin(DME)in the plasma using UPLC at the same time,then we obtained the time-effect and time-dose curves.The rational daily administration times of YCHD when treating experimental jaundice were determined based on the comprehensive analysis of time-effect and time-concentration relationships.Results Within 10 h the total bile of rats which were administered once daily(G1) was 1.65 and 1.33 times higher than that of twice and thrice(G2 and G3)a day,respectively,and the four biochemical indexes(TBIL,ALT,DBIL,and AST)of G1 decreased faster than those of G2 and G3(P<0.05).On the other hand, the blood drug level of DME when administrated once daily could maintain at a higher level for a longer time,and its Cmax and AUC0→t were higher than those of G2 and G3,which might be the main reason why its effect was the most significant.Conclusion It is more appropriate to administrate once daily when YCHD is used to treat jaundice.展开更多
This paper presents the results of an experimental investigation on the variation in the tension and the distribution of drag force coefficients along flexible risers under vortex-induced vibration（VIV） in a uniform...This paper presents the results of an experimental investigation on the variation in the tension and the distribution of drag force coefficients along flexible risers under vortex-induced vibration（VIV） in a uniform flow for Reynolds numbers（Re） up to 2.2×10^5. The results show that the mean tension is proportional to the square of the incoming current speed, and the tension coefficient of a flexible riser undergoing VIV can be up to 12. The mean drag force is uniformly and symmetrically distributed along the axes of the risers undergoing VIV. The corresponding drag coefficient can vary between 1.6 and 2.4 but is not a constant value of 1.2, as it is for a fixed cylinder in the absence of VIV. These experimental results are used to develop a new empirical prediction model to estimate the drag force coefficient for flexible risers undergoing VIV for Reynolds number on the order of 10^5, which accounts for the effects of the incoming current speed, the VIV dominant modal number and the frequency.展开更多
In this paper, the hydrodynamic coefficients of a horizontal semi-immersed cylinder in steady current and oscillatory flow combining with constant current are obtained via forced oscillation experiments in a towing ta...In this paper, the hydrodynamic coefficients of a horizontal semi-immersed cylinder in steady current and oscillatory flow combining with constant current are obtained via forced oscillation experiments in a towing tank. Three nondimensional parameters(Re, KC and Fr) are introduced to investigate their effects on the hydrodynamic coefficients.The experimental results show that overtopping is evident and dominates when the Reynolds number exceeds 5×105 in the experiment. Under steady current condition, overtopping increases the drag coefficient significantly at high Reynolds numbers. Under oscillatory flow with constant current condition, the added mass coefficient can even reach a maximum value about 3.5 due to overtopping while the influence of overtopping on the drag coefficient is minor.展开更多
This study proposed a method to obtain hydrodynamic forces and coefficients for a flexible riser undergoing the vortex-induced vibration(VIV), based on the measured strains collected from the scale-model testing with ...This study proposed a method to obtain hydrodynamic forces and coefficients for a flexible riser undergoing the vortex-induced vibration(VIV), based on the measured strains collected from the scale-model testing with the Reynolds numbers ranging from 1.34 E5 to 2.35 E5. The riser is approximated as a tensioned spatial beam, and an inverse method based on the FEM of spatial beam is adopted for the calculation of hydrodynamic forces in the cross flow(CF) and inline(IL) directions. The drag coefficients and vortex-induced force coefficients are obtained through the Fourier Series Theory. Finally, the hydrodynamic characteristics of a flexible riser model undergoing the VIV in a uniform flow are carefully investigated. The results indicate that the VIV amplifies the drag coefficient, and the drag coefficient does not change with time when the CF VIV is stable. Only when the VIVs in the CF and IL directions are all steady vibrations, the vortex-induced force coefficients keep as a constant with time, and under"lock-in" condition, whether the added-mass coefficient changes with time or not, the oscillation frequency of the VIV keeps unchanged. It further shows that the CF excitation coefficients at high frequency are much smaller than those at the dominant frequency, while, the IL excitation coefficients are in the same range. The axial distributions of the excitation and damping region at the dominant frequency and high frequency are approximately consistent in the CF direction, while, in the IL direction, there exists a great difference.展开更多
基金National Natural Science Foundation of China (81073069)
文摘Objective To study the rational daily administration times of Yinchenhao Decoction(YCHD)when it was used to treat experimental jaundice in rats based on pharmacodynamics/pharmacokinetics model.Methods Rats were modeled by 4%1-naphthylisothiocyanate(75 mg/kg)for 48 h,then YCHD was drenched with doses of 0.324 g/kg (extract,calculated with the clinical dosage)once,0.162 g/kg twice,and 0.108 g/kg thrice a day,respectively.The total bile and the flow rate of bile were observed after the first administration;Blood samples collected from the orbital sinus at different intervals were used to investigate the levels of liver enzymes(ALT and AST)and bilirubins (TBIL and DBIL),and determine the concentration of 6,7-dimethoxycoumarin(DME)in the plasma using UPLC at the same time,then we obtained the time-effect and time-dose curves.The rational daily administration times of YCHD when treating experimental jaundice were determined based on the comprehensive analysis of time-effect and time-concentration relationships.Results Within 10 h the total bile of rats which were administered once daily(G1) was 1.65 and 1.33 times higher than that of twice and thrice(G2 and G3)a day,respectively,and the four biochemical indexes(TBIL,ALT,DBIL,and AST)of G1 decreased faster than those of G2 and G3(P<0.05).On the other hand, the blood drug level of DME when administrated once daily could maintain at a higher level for a longer time,and its Cmax and AUC0→t were higher than those of G2 and G3,which might be the main reason why its effect was the most significant.Conclusion It is more appropriate to administrate once daily when YCHD is used to treat jaundice.
基金financially supported by the National Natural Science Foundation of China(Grant No.51490674)
文摘This paper presents the results of an experimental investigation on the variation in the tension and the distribution of drag force coefficients along flexible risers under vortex-induced vibration（VIV） in a uniform flow for Reynolds numbers（Re） up to 2.2×10^5. The results show that the mean tension is proportional to the square of the incoming current speed, and the tension coefficient of a flexible riser undergoing VIV can be up to 12. The mean drag force is uniformly and symmetrically distributed along the axes of the risers undergoing VIV. The corresponding drag coefficient can vary between 1.6 and 2.4 but is not a constant value of 1.2, as it is for a fixed cylinder in the absence of VIV. These experimental results are used to develop a new empirical prediction model to estimate the drag force coefficient for flexible risers undergoing VIV for Reynolds number on the order of 10^5, which accounts for the effects of the incoming current speed, the VIV dominant modal number and the frequency.
基金financially supported by the SINTEF Fisheries and Aquaculture of Norway and the National Natural Science Foundation of China(Grant No.51490674)
文摘In this paper, the hydrodynamic coefficients of a horizontal semi-immersed cylinder in steady current and oscillatory flow combining with constant current are obtained via forced oscillation experiments in a towing tank. Three nondimensional parameters(Re, KC and Fr) are introduced to investigate their effects on the hydrodynamic coefficients.The experimental results show that overtopping is evident and dominates when the Reynolds number exceeds 5×105 in the experiment. Under steady current condition, overtopping increases the drag coefficient significantly at high Reynolds numbers. Under oscillatory flow with constant current condition, the added mass coefficient can even reach a maximum value about 3.5 due to overtopping while the influence of overtopping on the drag coefficient is minor.
基金Supported by Shanghai Science and Technology Program (Grant No.19JC141280119JC1412802)+1 种基金Joint Funds of the National Natural Science Foundation of China (Grant No.U19B2013)the NationalScience Fund for Distinguished Young Scholars (Grant No.51825903)。
基金financially supported by the National Natural Science Foundation of China(Grant No.51490674)
文摘This study proposed a method to obtain hydrodynamic forces and coefficients for a flexible riser undergoing the vortex-induced vibration(VIV), based on the measured strains collected from the scale-model testing with the Reynolds numbers ranging from 1.34 E5 to 2.35 E5. The riser is approximated as a tensioned spatial beam, and an inverse method based on the FEM of spatial beam is adopted for the calculation of hydrodynamic forces in the cross flow(CF) and inline(IL) directions. The drag coefficients and vortex-induced force coefficients are obtained through the Fourier Series Theory. Finally, the hydrodynamic characteristics of a flexible riser model undergoing the VIV in a uniform flow are carefully investigated. The results indicate that the VIV amplifies the drag coefficient, and the drag coefficient does not change with time when the CF VIV is stable. Only when the VIVs in the CF and IL directions are all steady vibrations, the vortex-induced force coefficients keep as a constant with time, and under"lock-in" condition, whether the added-mass coefficient changes with time or not, the oscillation frequency of the VIV keeps unchanged. It further shows that the CF excitation coefficients at high frequency are much smaller than those at the dominant frequency, while, the IL excitation coefficients are in the same range. The axial distributions of the excitation and damping region at the dominant frequency and high frequency are approximately consistent in the CF direction, while, in the IL direction, there exists a great difference.
基金Supportted by the National Natural Science Foundation of China(Grant No.51279101,51490674 and 51490675)National Basic Research Program of China(973 Program-2013CB036103)the High-Tech Ship Research Projects of the Ministry of Industry and Information Tec
